2026-05-14 九州大学
【参考図】流動する赤血球の内部と周囲，そして組織における酸素動態の数値シミュレーションの例。
＜関連情報＞
- https://www.kyushu-u.ac.jp/ja/researches/view/1476
- https://www.sciencedirect.com/science/article/pii/S0017931026004989
微小循環における血流ダイナミクス下での酸素輸送と代謝に対する拡散界面アプローチ Diffuse interface approach to oxygen transport and metabolism under blood flow dynamics in microcirculations
Naoki Takeishi, Junya Kobayashi, Shigeo Wada, Satoshi Ii
International Journal of Heat and Mass Transfer Available online: 27 April 2026
DOI:https://doi.org/10.1016/j.ijheatmasstransfer.2026.128822
Highlights
- A diffuse interface model is developed for oxygen transport in cellular-scale blood flows.
- The mixture formulation enables the seamless treatment of interfacial jumps.
- Clarifying a relationship between cellular dynamics and tissue oxygenation in microvascular system.
Abstract
The relationship between the spatiotemporal distribution of oxygen transport and blood flow dynamics, accounting for the motion and deformation of individual red blood cells (RBCs), is of fundamental importance for understanding microcirculation systems. Three-dimensional (3D) modeling is indispensable for addressing complex oxygen transport and cellular behaviors in capillary networks; however, the computational approach is formidable for enforcing interface (or jump) conditions on largely moving and deforming interfaces. In this paper, we propose a diffuse interface approach for the oxygen transport using a mixture formulation. We formulate oxygen transport using an advection–diffusion–reaction equation and rewrite all governing equations in mixture forms using phase indicator functions, where all the interface conditions are included in the governing equations. This innovation avoids the complexity associated with discontinuities for largely moving interfaces in highly dense RBC conditions. We model cellular flow as a fluid–membrane interaction problem using the immersed boundary method (IBM). The method allows the seamless calculation of coupling problems for cellular flows and oxygen transports in the cytoplasm (internal fluid) of the RBC, plasma (external fluid), and tissue regions using a fixed Cartesian coordinate mesh. The proposed method accurately captures the analytical solution for spherically symmetric diffusion, and successfully demonstrates oxygen transport in both straight capillaries and their networks. These rigorous analyses suggest that RBCs can autonomously regulate the oxygen supply to tissues in response to the local tissue oxygenation level, resulting in the establishment of homogeneous tissue oxygenation.
